WASHINGTON — Sens. Patrick Leahy and Bernie Sanders are opposing a pending Federal Communications Commission proposal to alter current restrictions on media ownership, charging that it could increase concentration and threaten diversity in the communications marketplace.

In a letter to FCC Chairman Julius Genachowski late last week, Leahy and Sanders joined seven other senators — all Democrats — in urging the FCC not to consider eliminating current rules that bar a single company from owning both newspapers and TV stations in the same market.

The senators pointed to newly released FCC data showing that women own less than 7 percent of full-power commercial radio and TV stations, “while racial and ethnic minorities control only 5 percent of these TV stations and 8 percent of these radio stations.”

“Despite the extremely low levels of female and minority ownership, we understand the FCC is again considering relaxation of its cross-ownership rules, which include limits on ownership of television stations and newspapers in the same market,” the letter continued. “The changes appear to be very similar to the rules changes that former FCC Chairman Kevin Martin proposed in 2007 and that the public, the Senate, and a federal appeals court resoundingly rejected.”

The reference was to a 2008 Senate resolution and a 2011 ruling by the U.S. Court of Appeals for the 3rd Circuit.

In a statement Thursday, Leahy, who is chairman of the Senate Judiciary Committee, said, “Admitting local voices to the conversation and promoting diverse viewpoints is an American value, a Vermont value and a cornerstone of democracy.”

He added: “While the Internet is an important alternative to traditional broadcast media, it is not yet a sufficient replacement, particularly in rural areas like Vermont where Internet access is not universal. I have long opposed efforts to loosen media ownership rules, and I continue to believe that weaker rules would lead to greater consolidation and less diversity and local content.”

During a Thursday news conference with Sen. Maria Cantwell, D-Wash., at the Capitol, Sanders charged the FCC’s proposal constituted a threat to democracy and freedom of speech.

“Here in America, where we pride ourselves on how robustly we exercise our freedom of speech, control over the discussions in the public square has been drastically concentrated in the past 30 years,” he said, adding. “In 1983, 90 percent of American media were owned by 50 companies. Today, that same 90 percent of media are controlled by six giant companies.”

He specifically mentioned General Electric Co., Disney, Viacom, Time Warner, CBS, and NewsCorp — the last of which is controlled by media baron Rupert Murdoch.

According to published reports, the FCC has been considering a draft order that would lift the ban on one company owning both a newspaper and TV station in the top 20 markets. Bans on the same company owning both a newspaper and radio station or a TV and radio station would reportedly be lifted in all markets.

However, in a statement this week, Bill Lake, chief of the FCC’s Media Bureau, asserted that “reports that the order would make it easier to own a top TV station and a major newspaper in a market are wrong.”

Said Lake: “In fact, the order would strengthen the current rule by creating an express presumption against a waiver of the cross-ownership ban to allow such a combination. In addition, the proposed order preserves the existing TV duopoly rule, which forbids ownership of more than one of the top four TV stations in any market.”

Lake also announced this week that the FCC was extending the comment period on this matter for another 30 days, putting off any decision by the five-member commission until January 2013 at the earliest. Every four years the FCC is required to review its ownership rules and determine whether they are in the public interest as the result of competition.